The invention relates generally to printing systems, and more particularly to modular printer systems having a depleting ribbon supply roll and a heated print-head for transferring ink from the ribbon onto a substrate, which may be moving continuously, particularly in coding and marking operations.
In the manufacturing and packaging of many products it is often desirable to print variable information on the product directly or on its packaging in marking and coding operations. The food, beverage and pharmaceutical industries, for example, frequently print lot numbers, expiration dates, production codes, pricing and other variable information on articles, and labels and packaging therefor, all of which are referred to herein generally as substrate.
One particular type of printer system suitable for marking and coding operations includes generally an inked print ribbon transferred from a ribbon supply roll disposed on an unwind reel, to a print position adjacent a print-head, or typeholder, and then to a rewind reel, about which ink depleted ribbon is wound. The ribbon is advanced intermittently between the typeholder and the substrate, usually during or between printing operations, wherein the typeholder is selectively actuatable, either rotationally or linearly, to transfer ink from the ribbon onto a target area of the substrate at the print position, thereby printing or imprinting information thereon.
In the past, many coding and marking printer systems were operated pneumatically, including among other operational aspects of the systems actuation of the typeholder and advancement of the ribbon. More recently, however, there has been a trend in the manufacturing and packaging industries to eliminate from their facilities compressed air supply systems, which increase infrastructure, operational and maintenance costs. Also, usage of compressed air is very often a source of product contamination, particularly in the food processing and packaging industries. Pneumatically operated coding and marking systems arc thus being replaced increasingly with electrically operated systems, which are less costly and less problematic.
One problem associated with coding and marking systems that supply ribbon from a ribbon supply roll is a tendency toward decreasing drag on the ribbon as the ribbon supply roll is depleted, which results generally from the decreasing mass and diameter, or size, thereof. This is true more generally of any system that supplies a continuous web from a depleting web supply roll. It is generally desirable however to maintain relatively constant drag on the ribbon or web to provide improved control over the supplying thereof. It is especially desirable to maintain relatively constant drag on ribbon supplied in coding and marking systems that advance ribbon intermittently with an electric motor having a fixed driving torque as disclosed in the present invention.
Many coding and marking systems also include a heated typeholder for transferring ink from the print ribbon onto the substrate. One such typeholder, for example, is a rotatable typeholder configurable with variable type nearly completely disposed in a radiant oven, or heater block, except for a portion thereof, which is protrudable from an opening of the heater block during printing operations. A problem common to heater blocks, and more particularly to heated typeholders, is a tendency to radiate away heat, thereby reducing the efficacy of ink transfer from the ribbon onto the substrate and increasing operating costs. It is thus desirable to reduce radiant heat loss from the typeholder, particularly in applications where the orientation of the heater block promotes radiant heat loss. In vertical form, fill and seal packaging operations, for example, product is gravity fed vertically into a partially formed package, which is supplied from a generally horizontal continuous substrate where the coding and marking operations are performed before the forming and filling operations. Coding and marking systems for printing on horizontally moving substrates though are nearly always oriented below the substrate so that the opening of the heater block and typeholder face upwardly, whereby heat radiation away therefrom is substantial.
Since most coding and marking systems are operated and serviced by personnel not knowledgeable with the intricacies thereof, the systems must be relatively simple and highly reliable. It is often desirable therefore to mount the ribbon unwind and rewind reels on a cassette assembly that is readily removably mountable onto a main plate assembly, thereby facilitating replacement of ink depleted print ribbon supply rolls and providing access to the interior thereof for maintenance. Removable cassette assemblies are known generally, but it is desirable to provide an improved cassette assembly that is more readily and accurately alignable and spaced relative to the main plate assembly. It is also desirable to provide a cassette assembly that is positively lockingly engageable to the main plate assembly economically and reliably.
The present invention is therefore drawn generally toward novel advancements in the art of printing systems, and more particularly to improvements applicable to printer systems having a depleting ribbon supply roll and a heated typeholder useable for coding and marking operations on continuously moving substrates.
It is an object of the invention to provide novel printing systems, especially coding and marking printer systems, that overcome problems in the prior art by improving various aspects of prior art printing systems including improved ribbon drag control, improved heater block insulation, improved system modularity, and combinations thereof, all of which have improved economics and reliability.
It is a more particular object of the invention to provide novel printer systems, particularly coding and marking printer systems, comprising an unwind reel coupled to a rotatable drag pulley to supply ribbon from a depletable ribbon supply roll disposed thereon to a typeholder and then to a rewind reel, which winds ink deplete ribbon thereabout. The ribbon is supplied generally from the unwind reel to a first guide roller, to a dancer guide roller on a pivotal dancer arm, and then to the rewind reel. A drag belt disposed partially about the drag pulley has a first end coupled to the dancer arm on a first side of its pivot axis and a second end coupled to the dancer arm on a second side of the pivot axis. The dancer arm is pivotal about its axis to control tension on the drag belt as ribbon is supplied from the unwind reel, whereby drag on the unwind reel increases generally as the ribbon supply roll decreases in size to maintain relatively constant drag thereon.
It is another more particular object of the invention to provide novel printer systems of the type discussed generally above also comprising an electrically driven feed roller frictionally engageable with the ribbon to unwind ribbon from the unwind reel, and related thereto the feed roller may be rotatably coupled to the rewind reel about which ink deplete ribbon is wound, whereby an electric drive motor rotates both the rewind reel and the feed roller.
It is also an object of the invention to provide novel printer systems, particularly coding and marking printer systems, comprising a heated typeholder, which may be rotatable, actuatably disposed in an at least partially insulated heater block having one or more insulator members disposed adjacent one or more corresponding surfaces thereof, preferably adjacent upwardly directed surfaces thereof, whereby the insulator members reduce heat radiation from the heater block and the typeholder. It is a related object of the invention to provide one or more insulator members disposed adjacent corresponding surfaces adjacent an opening of the heater block, through which the typeholder is protrudable during printing operations, thereby reducing heat radiation therefrom, particularly when the heater block is oriented with its opening and the typeholder directed upwardly.
It is a further object of the invention to provide novel modular printer systems, particularly modular coding and marking printer systems, comprising a main plate assembly wherein an unwind reel, a dancer arm and a rewind reel are mounted on a cassette assembly removably and lockingly mountable to the main plate assembly. It is a related object of the invention to provide a main plate assembly having one or more alignment members protruding therefrom, and the cassette assembly having apertures for receiving corresponding alignment members of the main plate assembly when the cassette assembly is mounted thereto, wherein the alignment members are disposeable in the apertures of the cassette assembly to align and or space the cassette assembly relative to the main plate assembly. It is yet another related object of the invention to provide a sliding block having an end portion biased over a portion of an aperture of the cassette assembly for receiving an alignment member of the main plate assembly having a recess, whereby an end portion of the sliding block is engageable with the recess of the alignment member to lockingly retain the cassette assembly mounted to the main plate assembly.
These and other objects, features, aspects and advantages of the present invention will become more fully apparent upon careful consideration of the following Detailed Description of the Invention and the accompanying Drawings, which may be disproportionate for ease of understanding, wherein like structure and steps are referenced generally by corresponding numerals and indicators.